Cover and cook on the low heat setting 6 to 6
1/2 hours or until the beef is just tender. Increase the heat
setting to high. Stir in the green and red pepper squares and
the brown sugar. Mix together the cornstarch, soy sauce and
remaining 2 tablespoons vinegar. Stir into the cooker, blending
well.

Cook, covered, on high 45 to 60 minutes,
stirring occasionally, until the sauce thickens slightly.

Just before serving, stir in the tomato
wedges and pineapple chunks. Serve over cooked white rice.